I purchased a rear view mirror with the screen built in. The camera mounts on the rear of the vehicle through a hole in the bumper or a mounting plate on the hitch. I like the idea of a second camera on the rear of the trailer and I was wondering if it is a simple as only applying voltage to the one you want to use. I haven't installed it yet but I like the idea of two cameras. I bought it through J.C. Whitney for much less than there internet price. Check thier catalogs and the coupons inside them. Hope this hels somone.
Thanks, Doug

Well, it wouldn't let me post the link but check thier website at www.jcw.com and go to the mirrors section. It is the automan unit with the rear mounted camera. Good luck